 made up of all waters between continents…”The World Ocean”  because waters are interconnected can be thought of as one large biome with many different ecosystems and habitats  Not all ocean waters have the same characteristics  Each have waters that flow in characteristic patterns

A. Defining characteristics Due to energy receive from sun: Temperature Salinity Density

Examples: TropicsPolar Near equator = increase in energy from sun Increase in energy = increase in temperature Increase in temperature = increase in evaporation rate Increased evaporation = increase in salinity and mineral content Fed by melting glaciers\polar ice = increase in colder freshwater Increase in colder freshwater = decrease in temperature Decrease in temperature = decrease in evaporation rate Decreased temperature and evaporation rates = increased freshwater = decrease in salinity and mineral content and increase in density

Ocean Currents Driven mostly by winds May vary somewhat during the year or from year to year but most are stable Because of currents one mass of water may vary greatly from adjacent waters Fish and other ocean organisms often travel along with specific currents

Both Vertical and Horizontal Zones

A. Vertical Zones 1. PHOTIC – receives light 2. APHOTIC- does not receive light 3. BENTHIC- floor, can be in both photic and aphotic zones

B. Horizontal Zones 1. Intertidal- along the coastline, lying between high tide and low tide marks. 2. Neritic- lies between the edge of the continental shelf and the low tide mark 3. Oceanic- ranges from about 200 m along the continental slopes to 11,000 m below the surface

1. Intertidal Zone:  Along the coast  Exposed during low tide  Submerged during high tide  Organisms –  must be able to survive in both submerged and exposed conditions  as well as the constant pounding of the surf.  Adaptations= attaching to rocks or burrowing  Often surrounded by :  Tidal Salt Marshes  Mangrove Swamps

a.Salt Marshes  Flat, muddy wetlands that often surround estuaries, bays and lagoons.  Form when streams flow into calm waters of estuaries or shallow neritic waters  Slowing of the streams=sedimentation around mouth of stream= Subsidence  Influenced by tides, exposed during low tides and drought and submerged during high tide and rainy periods.  Common form of wetland along U.S. coast(Gulf of Mexico)…Mississippi River Delta  Most important role=supporting migratory bird populations  Other important role= supporting ocean ecosystems…plants communities support increase communities of fishes and invertebrates

b. Mangrove Swamps  Coastal wetlands, only in warmer climates  Frost kills plants in a mangrove swamp  Dominant plant life=mangrove plant  68 species worldwide  10 U.S. species  Red mangrove= most common  Water quality= very low dissolved oxygen  Plant adaptation= root systems that emerge from water  Mangrove swamps are destroyed for many reasons:  Aquaculture ponds=raising commercial fish and shrimp  Coastal construction properties  Waste dumping

2. Neritic Zone  Ocean region between the edge of the continental shelf and the low tidemark  Continental shelf- shallow border that surrounds the continents,  area between shore and about 200m below water surface  Shallow warmer waters  Most productive part of the ocean  Two very productive ecosystems: 1. Coral Reefs 2. Estuaries  Factors that contribute to productivity:  Sunlight can reach benthic zone of continental shelf which allows photosynthesis to occur  Waters tend to be high in mineral nutrients  Tides wash fresh supply of nutrients and oxygen over zone and takes away waste

a. Reefs Natural structure built on continental shelf Made up of calcium carbonate skeletons of millions of tiny corals Coral reefs = warmer, tropical waters Kelp reefs (beds)= cooler waters Coral reefs = symbiotic relationship with zooxanthellae algae that live inside tissues of corals, carry out photosynthesis = food Human Activities harm reefs in many ways: 1. Often blasted with dynamite building harbors and shipping channels 2. Harvested, sold as jewelry 3. Bright, colorful fishes popular for home aquariums 4. methods used to harvest fish 5. Water pollution: toxic chemicals washed from land Silt, sand, topsoil, fertilizers=make waters more cloudy Tides effect reef formation over time Fringe reefs- first formed, grows just off shore Barrier reefs- separated by channel from shore over time Great Barrier Reef in Australia is the largest

CORAL REEF KELP REEF

b. Estuaries  A region where a freshwater source, usually the mouth of a river, meets the salt water of the ocean  Water is usually brackish  Salinity varies by :  Depth  Time of year  Flow rate  Tide  Function as:  Spawning grounds for many marine organisms  Important buffering zones  Filtering sediments and pollutants from the water  Ease effects of storms and floods by slowing water flow  Human use for recreational use such as boating, hunting and fishing

3. Oceanic Zone o “open ocean” o Largest ocean zone, 90% of ocean surface area o Very deep, ranging from 200m to about 11,000m below surface o Sunlight does not penetrate deeply only photic zone o Only producers are phytoplankton o Convert CO2 into organic carbon = biomass for base of food web o Major food source for many larger animals…..ex.) baleen whales o Detritus – another food source at bottom of food web, tiny pieces of dead organic material o Food source for benthic Invertebrates such as: clams, worms, sponges o Aphotic zones = “desert of marine biomes” due to lack of sunlight which limits diversity o Deep ocean organisms must be adapted to: cold, dark, and deep waters

 People have dumped pollutants at sea for many years believing they would be diluted to safe levels by vast currents.  However many pollutants can become concentrated in fish being eaten by humans  The Ocean Dumping Act- (1988) banned the disposal of industrial wastes at sea